Underdrive Pully???
02-17-2009, 04:01 PM
#21
As far as it being to small to control crankshaft harmonics, then what about the people who have pulleys along side lightweight flywheels or smaller converters. Especially those with built motors whose balance may be far worse than factory. They aren't breaking chains like that guy.
It may not have helped anything in that case, but it didn't cause it.
It may not have helped anything in that case, but it didn't cause it.
The greater the inertia mass of any given damper, the greater its potential is for countering the torsional twisting or harmonic vibrations of the crankshaft.
A typical damper with an 8" diameter will almost always be more effective at reducing torsional twisting than a 6" damper, simply because the 8" damper has a greater inertia mass.
A typical damper with an 8" diameter will almost always be more effective at reducing torsional twisting than a 6" damper, simply because the 8" damper has a greater inertia mass.
Wheel to Wheel saw these problems repeatedly during development of the Motorola Cup cars. The solution was a timing chain damper and lower durometer rubber in the crankshaft damper.
02-17-2009, 06:12 PM
#23
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Remember as for cooling with underdriven pulley, most modded LS motors idle and spin at higher rpm than stock motors so waterpump rpm is brought back closer to OEM speeds with stock pulley. I agree smaller diameter balancer/pulley will not dampen vibration as effectively as larger unit, but other things weigh in like the proper interference fit with crankshaft snout. This can make or break the effectiveness of balancer. Engine balance and detonation can wreak havoc on a timing chain too. A aftermarket sprocket set may not have perfect line up gear to gear also. This will wear chain and load it excessively. How many do it your selfers here lay a straight edge on the two gears and than correct any difference? Food for thought.
02-17-2009, 06:59 PM
#25
Remember as for cooling with underdriven pulley, most modded LS motors idle and spin at higher rpm than stock motors so waterpump rpm is brought back closer to OEM speeds with stock pulley. I agree smaller diameter balancer/pulley will not dampen vibration as effectively as larger unit, but other things weigh in like the proper interference fit with crankshaft snout. This can make or break the effectiveness of balancer. Engine balance and detonation can wreak havoc on a timing chain too. A aftermarket sprocket set may not have perfect line up gear to gear also. This will wear chain and load it excessively. How many do it your selfers here lay a straight edge on the two gears and than correct any difference? Food for thought.
02-17-2009, 08:21 PM
#26
It's a direct cause and effect 'assumption' for the most part. Not ignoring facts, as there aren't any to ignore. It may be as simple as installation error on the ones that could truely by UDP caused.
Though, I personally would give it a hard thought before installing a pulley on an LS3, it really isn't an issue for Gen III guys. Which is the issue here. And if you know of UDP related failures for LS1s, please post them.
Though, I personally would give it a hard thought before installing a pulley on an LS3, it really isn't an issue for Gen III guys. Which is the issue here. And if you know of UDP related failures for LS1s, please post them.
02-17-2009, 08:54 PM
#27
Without searching, I'm sure it's just more theory on why it could go wrong. More often than not problems arise from bad installs. Can you guarantee there was no other problems with said chains and that the balancer was install correctly. No you can't.
I hear you on the LS3s, new product could have problems. But by the shear volume of UDPs sold for everything else. I say chances of having a problem are slim if it is the fault of the UDP.
I hear you on the LS3s, new product could have problems. But by the shear volume of UDPs sold for everything else. I say chances of having a problem are slim if it is the fault of the UDP.
I didn't think so......
Quantity sold does not validate quality and effectiveness.
02-17-2009, 08:54 PM
#28
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Think of it this way, on a M6 car, the 25% reduction would slow all the accessories down to the same speed as an A4. So I don't see any problems with it. And from what I remember of my heat transfer classes, the cooling system on most automobiles are designed to handle approximately 75% of the max power output for the engine. The only vehicles that are usually 100% or more are semi's. And that's only because they are constantly trying to make peak power to tow loads.
02-17-2009, 09:02 PM
#29
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Without searching, I'm sure it's just more theory on why it could go wrong. More often than not problems arise from bad installs. Can you guarantee there was no other problems with said chains and that the balancer was install correctly. No you can't.
I hear you on the LS3s, new product could have problems. But by the shear volume of UDPs sold for everything else. I say chances of having a problem are slim if it is the fault of the UDP.
I hear you on the LS3s, new product could have problems. But by the shear volume of UDPs sold for everything else. I say chances of having a problem are slim if it is the fault of the UDP.
02-17-2009, 09:04 PM
#30
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Think of it this way, on a M6 car, the 25% reduction would slow all the accessories down to the same speed as an A4. So I don't see any problems with it. And from what I remember of my heat transfer classes, the cooling system on most automobiles are designed to handle approximately 75% of the max power output for the engine. The only vehicles that are usually 100% or more are semi's. And that's only because they are constantly trying to make peak power to tow loads.
02-17-2009, 09:06 PM
#31
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So lets here some more constructive conversation please..
02-17-2009, 09:28 PM
#34
That post was more useless than an LT1's cupholder.
Clearly, I'm aware of that solution. I'm trying to see if there is a causal relationship between an ASP pulley and a broken chain - and if there is one what the potential cause could be, so I can make an education decision whether I should buy a pulley, and if so, what to look for.
Clearly, I'm aware of that solution. I'm trying to see if there is a causal relationship between an ASP pulley and a broken chain - and if there is one what the potential cause could be, so I can make an education decision whether I should buy a pulley, and if so, what to look for.
02-17-2009, 09:35 PM
#35
The answer you're gonna get in this thread is "ASP causes chains to break" and "I only use ATIs" and that's about it.
I have proof that my chains hasn't broken yet and I know other peoples chains that haven't broken from ASP pulleys. And I know that everytime one becomes available in the classifieds that it sells in minutes. Does that prove that it won't cause problems, no. But if they were that bad it wouldn't take long for everyone to know it.
I mean have you ever heard anything good about flowmasters on this board? Make a thread and see how many negative posts it gets. Then make on about ASP pulleys and see how many broke chain stories you get. It'll be the same one listed in this thread maybe another one, but I doubt that.
You might get lucky and you might not, but you're not gonna get a good answer to your question.
I have proof that my chains hasn't broken yet and I know other peoples chains that haven't broken from ASP pulleys. And I know that everytime one becomes available in the classifieds that it sells in minutes. Does that prove that it won't cause problems, no. But if they were that bad it wouldn't take long for everyone to know it.
I mean have you ever heard anything good about flowmasters on this board? Make a thread and see how many negative posts it gets. Then make on about ASP pulleys and see how many broke chain stories you get. It'll be the same one listed in this thread maybe another one, but I doubt that.
You might get lucky and you might not, but you're not gonna get a good answer to your question.
02-17-2009, 10:38 PM
#38
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Nope, one guy broke an LS3 timing chain and the other an LS3 and a double roller. Do a search for people that have broken timing chains and look at the common denominators. You can ignore it, but it won't make it go away.
Torque converters and flywheels are not engine dampers and will not control 2nd, 3rd, and 4th order harmonics like the correct damper. The only component designed to dampen crankshaft harmonics is the crankshaft damper. An out of balance torque converter or flywheel with cause other vibrations in the engine damaging other components. Engine balance and harmonics control are two different aspects with a slight overlap.
Reference: Fluidamper
Wheel to Wheel saw these problems repeatedly during development of the Motorola Cup cars. The solution was a timing chain damper and lower durometer rubber in the crankshaft damper.
Torque converters and flywheels are not engine dampers and will not control 2nd, 3rd, and 4th order harmonics like the correct damper. The only component designed to dampen crankshaft harmonics is the crankshaft damper. An out of balance torque converter or flywheel with cause other vibrations in the engine damaging other components. Engine balance and harmonics control are two different aspects with a slight overlap.
Reference: Fluidamper
Wheel to Wheel saw these problems repeatedly during development of the Motorola Cup cars. The solution was a timing chain damper and lower durometer rubber in the crankshaft damper.
JonCR96Z
Read the post above it specifically states that a 8" damper will always be better than a 6" damper. So please tell me were he said that a smaller pulley is better for dampening? At this point your just post whoring and not contributing to the thread..
02-17-2009, 11:59 PM
#40
Ok so I am going to be doing heads and cam on my 99 camaro Z28 M6 here pretty soon. I had a underdrive pully on my previous LS1 car and never had a problem. But I was giving it some thought and cant decide if the power gains is worth it or not. Basically my question is, Is it safe to be underdriving the water pump?? I am sure the GM engineers put alot of time and effort into making the water pump flow just right for the engine, and taking flow away could cause problems IMO. So lets here what you guys think.. 
This is not just a water pump question, but a complete accessory drive question that's pretty complex. I built a spreadsheet to analyze pulley ratios for each component based on stock pulley measurements and aftermarket damper diameters.
When using a drive pulley with a different diameter all of the accessories are affected. Each accessory has specific requirements for pulley ratios to maintain acceptable accessory RPM minimums and maximums.
Here is a picture of what I have, let me know if you want it and I'll upload it. You can play with the numbers and see how your system works out. Keep in mind you will need some specific water pump flow information to accurately estimate the information your looking for. This is many months of research.
Here you go:
